//snippet-sourcedescription:[StockTrade.java is a helper class]
//snippet-keyword:[SDK for Java 2.0]
//snippet-keyword:[Code Sample]
//snippet-service:[Amazon Kinesis Data Firehose]
//snippet-sourcetype:[full-example]
//snippet-sourcedate:[7/6/2020]
//snippet-sourceauthor:[scmacdon - aws]

/*
   Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
   This file is licensed under the Apache License, Version 2.0 (the "License").
   You may not use this file except in compliance with the License. A copy of
   the License is located at
    http://aws.amazon.com/apache2.0/
   This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied. See the License for the
   specific language governing permissions and limitations under the License.
*/

package com.example.firehose;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.atomic.AtomicLong;

/**
 * Generates random stock trades by picking randomly from a collection of stocks, assigning a
 * random price based on the mean, and picking a random quantity for the shares.
 *
 */

public class StockTradeGenerator {

    private static final List<StockPrice> STOCK_PRICES = new ArrayList<StockPrice>();
    static {
        STOCK_PRICES.add(new StockPrice("AAPL", 119.72));
        STOCK_PRICES.add(new StockPrice("XOM", 91.56));
        STOCK_PRICES.add(new StockPrice("GOOG", 527.83));
        STOCK_PRICES.add(new StockPrice("BRK.A", 223999.88));
        STOCK_PRICES.add(new StockPrice("MSFT", 42.36));
        STOCK_PRICES.add(new StockPrice("WFC", 54.21));
        STOCK_PRICES.add(new StockPrice("JNJ", 99.78));
        STOCK_PRICES.add(new StockPrice("WMT", 85.91));
        STOCK_PRICES.add(new StockPrice("CHL", 66.96));
        STOCK_PRICES.add(new StockPrice("GE", 24.64));
        STOCK_PRICES.add(new StockPrice("NVS", 102.46));
        STOCK_PRICES.add(new StockPrice("PG", 85.05));
        STOCK_PRICES.add(new StockPrice("JPM", 57.82));
        STOCK_PRICES.add(new StockPrice("RDS.A", 66.72));
        STOCK_PRICES.add(new StockPrice("CVX", 110.43));
        STOCK_PRICES.add(new StockPrice("PFE", 33.07));
        STOCK_PRICES.add(new StockPrice("FB", 74.44));
        STOCK_PRICES.add(new StockPrice("VZ", 49.09));
        STOCK_PRICES.add(new StockPrice("PTR", 111.08));
        STOCK_PRICES.add(new StockPrice("BUD", 120.39));
        STOCK_PRICES.add(new StockPrice("ORCL", 43.40));
        STOCK_PRICES.add(new StockPrice("KO", 41.23));
        STOCK_PRICES.add(new StockPrice("T", 34.64));
        STOCK_PRICES.add(new StockPrice("DIS", 101.73));
        STOCK_PRICES.add(new StockPrice("AMZN", 370.56));
    }

    /** The ratio of the deviation from the mean price **/
    private static final double MAX_DEVIATION = 0.2; // ie 20%

    /** The number of shares is picked randomly between 1 and the MAX_QUANTITY **/
    private static final int MAX_QUANTITY = 10000;

    /** Probability of trade being a sell **/
    private static final double PROBABILITY_SELL = 0.4; // ie 40%

    private final Random random = new Random();
    private AtomicLong id = new AtomicLong(1);

    /**
     * Return a random stock trade with a unique id every time.
     *
     */
    public StockTrade getRandomTrade() {
        // Pick a random stock
        StockPrice stockPrice = STOCK_PRICES.get(random.nextInt(STOCK_PRICES.size()));
        // Pick a random deviation between -MAX_DEVIATION and +MAX_DEVIATION
        double deviation = (random.nextDouble() - 0.5) * 2.0 * MAX_DEVIATION;
        // Set the price using the deviation and mean price
        double price = stockPrice.price * (1 + deviation);
        // Round price to 2 decimal places
        price = Math.round(price * 100.0) / 100.0;

        // Set the trade type to buy or sell depending on the probability of sell
        StockTrade.TradeType tradeType = StockTrade.TradeType.BUY;
        if (random.nextDouble() < PROBABILITY_SELL) {
            tradeType = StockTrade.TradeType.SELL;
        }

        // Randomly pick a quantity of shares
        long quantity = random.nextInt(MAX_QUANTITY) + 1; // Add 1 because nextInt() will return between 0 (inclusive)
        // and MAX_QUANTITY (exclusive). We want at least 1 share.

        return new StockTrade(stockPrice.tickerSymbol, tradeType, price, quantity, id.getAndIncrement());
    }

    private static class StockPrice {
        String tickerSymbol;
        double price;

        StockPrice(String tickerSymbol, double price) {
            this.tickerSymbol = tickerSymbol;
            this.price = price;
        }
    }

}
